Cardiac valve replacement may be required if the valve is prolapsed or otherwise malfunctioning. Replacement of a cardiac valve, such as, for example, the mitral or tricuspid valve, typically involves the resection of at least a portion of the diseased valve, leaving an annulus of host tissue, and the implantation of a prosthetic valve which includes a flexible ring and a plurality of leaflets mounted within the ring which are designed to open and close in response to changes in fluid pressure across them. The leaflets may be rotatable within the ring so that they can be oriented properly after the prosthesis has been implanted in the heart.
Prior art cardiac valve prostheses typically include a titanium ring and either two or three pyrolytic carbon leaflets (two if a mitral valve, three if a tricuspid valve). The ring is typically covered with a fabric cuff which promotes endothelialization of cardiac tissue into the prosthesis.
The prosthesis is generally secured to the annulus of native tissue at the valve site within the heart with a relatively large number of sutures which must be precisely placed and oriented so that the prosthesis does not rotate and the movement of the leaflets is not impeded when the prosthesis is in place. In practice, the prosthetic valve is secured to the host tissue using sutures attached to the fabric cuff surrounding the ring. Generally, relatively long sutures are passed through the tissue at the intended valve site and carefully laid out to extend through the incision in patient's chest, to points outside the incision. Then, the distal ends of the sutures are coupled to the cuff, and finally the valve and cuff arc "parachuted", or slid down the sutures, into place with the orientation of the valve maintained. The sutures anchoring the cuff of the prosthesis to the host tissue are then tied off.
Open-heart surgery is complicated, delicate, and confined. Minimally invasive surgical technologies and techniques are favored to minimize patient trauma; however, such procedures require a high degree of surgical skill. The implantation of a prosthetic valve with large numbers of sutures that cannot be crossed or otherwise twisted or misplaced is painstaking and difficult and prolongs the surgical procedure, thereby increasing patient trauma and the risk of infection. It would be an advancement in the art of cardiac valve replacement surgery to provide a valve which can be implanted without sutures.